1. Field of the Invention
This invention relates to a method for manufacturing flexible and rigid handle containers. More specifically, the present invention relates to the preparation of integral flexible and rigid handle containers from preforms or parisons by a technique, wherein flexible strings, molecularly oriented in their longitudinal direction, are molded in the neck area or rigid handles are incorporated laterally into rigid hooks formed into the bodies of the hollow articles. Rigid handle brackets may also encapsulate the hooks and flexible handles to form rigid handle containers.
2. Description of the Prior Art
Certain extrusion blow molded or accumulator blow molded synthetic materials have been found unsuitable for forming a handle container, wherein the extruded parison is inflated and a portion of same is pinched off to form an integral handle during the blow molding process. This is due to insufficient bonding capability of the synthetic materials in the pinched off area to produce a leak-proof container. Further injection blow molded or stretch blow molded preforms cannot be inflated to form a closed looped handle into the blown portion of a hollow article because the synthetic material does not allow to be blown or pinched around a handle island in a blow mold cavity. Efforts to overcome these limitations have focused upon the use of different styles of holding means on hollow articles. Thus, for example, U.S. Pat. No. 4,627,546 discloses a flexible detachable handle and carrier for a plastic bottle attached to a bottle neck and bottle bottom. U.S. Pat. No. 5,013,074 discloses a support handle which supports a container and retains its body. Japanese Patent 08-135,042, U.S. Pat. No. 5,988,418, U.S. Pat. No. 4,964,522, and U.S. Pat. No. 5,819,966 each disclose a handle fixed into a recess in a side portion of a synthetic resin bottle. European Patent 1,094,927 discloses a bottle with pins formed into the neck area to receive a handle. U.S. Pat. Nos. 4,629,598, 4,372,454, and 4,280,859, and international Patent WO 0,112,515 each disclose a method for forming a plastic bottle with an integral rigid handle of an L-shape projection, wherein a ring in the neck area extends outwardly and downwardly from the ring towards the center of the gravity of the bottle to act in concert with its side wall. U.S. Pat. No. 4,615,451 discloses a flexible string serving as a suspension loop for caps sunk into a groove to protect a closure flap during transport. U.S. Pat. No. 5,862,929, JP09-018813, and Israeli Patent No. 119,681 each describe a stretch-blown bottle with one lateral open-ended rigid handle formed below the threaded portion of the neck, which includes a narrow portion and which is transversally provided for molecular orientation of the synthetic material to make the handle bendable in this one narrow portion. U.S. Pat. No. 6,227,393 and Egyptian Patent No. 20,953 disclose a stretch-blown bottle with two lateral opposing open-ended rigid handles formed in the neck area. Each joining handle has a flat section extending in a transverse direction and parallel to the longitudinal axis of the bottle to achieve molecular orientation in this portion of each handle to make it bendable upwardly and downwardly at said reduced thickness portion. U.S. Pat. No. 6,196,403 discloses a hanging tool comprising a flat and long connection portion extending sideways from the neck portion and a detachable handle portion attached to the connection portion. U.S. Pat. No. 4,281,770 discloses a method wherein recesses in the wall of the container are shaped to receive an enlarged end of a separately molded handle with enlargements on both ends of the handle shaped to fit into the recesses but shaped to expand the entrances to the recesses so as to insert the ends of the handles which expand the entrances into the recesses for connecting and disconnecting the handles.
1. Purposes of the Invention
It is the object of the invention to mold at least two rigid hooks in opposing directions and a recess into the body of a hollow article. It is a further object of the invention to wrap a flexible string over the hooks and the recessed area to form a closed-loop, flexible handle container. It is a further object of the invention to laterally snap lock rigid handle halves between and over the hooks to form a rigid handle container. It is a further object of the invention to mold a preform, whereby the ends of at least one flexible string of varying thickness are molded into different neck areas beneath the threaded portion of the preform. It is a further object of the invention to transform the preform with at least one flexible string molded into different areas beneath the threaded area of the neck finish into a hollow article. It is the further object of the invention to lift at least one flexible string of varying thickness over the threaded area of the neck finish to form a flexible handle container. It is a further object of the invention to produce a preform with at least one short flexible string molded into the neck area beneath the threaded area of a preform. It is yet another object of the invention to transform the preform into a hollow article with at least one short flexible string molded into the neck finish beneath the threaded area and a recessed area and a hook molded into the body of the hollow article.
It is a further object of the invention to loop a separate flexible string around the hook, over the recess in the body of the hollow article and to fasten the ends of the open ended flexible string to at least one short flexible string molded into the neck area to form a flexible-handle container. It is a further object of the invention to loop a combination flexible and rigid handle string around the hook, over the recess in the body of the hollow article and to fasten the ends of the open ended combination flexible and rigid handle string to at least one short flexible string molded into the neck area to form a rigid handle container when the rigid handle portions have been snap locked together. It is a further object of the invention to produce a preform with at least one rigid holding means molded into the neck area of the preform. It is a further object of the invention to loop a flexible string around the hook and over the recess in the body of a blow molded hollow article and attach the two ends onto said rigid holding means. It is a further object of the present invention to produce a preform with the ends of at least one flexible string of varying thickness molded into its neck area. It is a further object of the invention to transform the preform into a hollow article with a recess and a hook formed in its body. It is a further object of the invention to uncurl and loop the flexible string across the recess and over the hook formed in the body of the hollow article to form a flexible handle container. It is a further object of the invention to place a rigid handle bracket between the hook in the body of the finished hollow article and its neck area encapsulating the flexible handle to form a rigid handle container. It is a further object of the invention to mold the flexible string of varying thickness with a clip, wherein the clip locks the flexible string in position above the hook to ascertain a firm grip of the loop onto the hook to form a flexible handle container. It is a further object of the invention to mold the flexible strings of varying thickness in their longitudinal direction to molecular orient the molten material in the narrow sections during injection to obtain flexibility and tensile strength. And lastly, it is an object of the invention to pass the molded strings through a post treatment unit to increase their flexibility and strength prior to assembly to form flexible-handle containers.
In accordance with the present invention, at least two rigid hooks and a recessed area are blow molded into the body of a hollow article. The term blow molding as employed herein includes at least stretch blow molding, extrusion blow molding, injection blow molding or accumulator head blow molding. Either a flexible or a rigid handle is mounted over the hooks and the recessed area to form a handle container. Alternatively, at least one short holding means is molded into the neck area and a hook means into the body of a hollow article. A flexible string or a rigid handle combined with a flexible string is looped over the hook and fastened to the short holding means to form a handle container. An alternative embodiment involves the use of a flexible string whose ends are molded into the neck area of a hollow article which can either be lifted above the neck area or looped over a hook formed in the body of the hollow article, so resulting in a flexible handle container. The flexible handle can be transformed into a rigid handle by encapsulating at least one flexible string with a separately formed rigid handle bracket.
Prior to applicant""s entry into the field, handle containers were either molded first with rigid pins in the neck area or recesses in a side portion of a bottle and handles of different synthetic materials are forced subsequently into said recesses or hollow articles with rigid L-shaped handles molded into the neck areas, whereby their lower extremities are somehow affixed to a blown portion of the containers, or containers with flat-shaped open-ended rigid handles extending into a transverse direction from the container""s neck areas with a bendable in an upward and downward direction in one narrow portion. The drawback of forcing rigid handles into recesses in the side portion of a bottle is that they need to be filled and capped or pressurized first to resist the bending pressures applied onto the flexible container walls when securing the rigid handle into the bottle main body.